The invention relates to a face shield comprising a lens.
Different shields to be fitted on the face are known. For example, masks are used by divers, fire fighters and soldiers, the structure of which varies depending on the purpose of use. Face and eye shields used by motorcyclists, cyclists, welding workers (e.g. a helmet with a visor) and other shields are also known. The present invention may be used with these types of devices.
In all of the above applications, the object of the shield is to protect a person from exceptional environmental strains. It will be appreciated that it is often useful for a person using protection to obtain information on environmental and other conditions so as to be able to work in the prevailing exceptional environment in an appropriate manner. For divers, in particular, it is useful to obtain plenty of information about diving.
In the following, a closer look will be taken at a shield in the form of a diving mask, since the invention is particularly focused, although not entirely, on such an application.
At present, diving masks include a display providing a diver with important information on diving such as depth and time of dive. The idea of the display including a dive computer is to make diving safer and to sensibly utilize the properties of the diving equipment and the diver. Dive computers thus offer information on, for example, a safe ascent rate so that the diver manages to avoid the dangers caused by ascending too fast.
GB patent application 2,277,451 discloses a diving mask to which a computer and optical means are integrated in order to provide the lens of the mask with said diving information.
GB patent application 2,283,333 discloses a diving mask including optical means integrated to it in order to provide the lens of the mask with said diving information. The computer controlling the display is either coupled to the diver's wrist or to the diver's air supply apparatus.
U.S. Pat. No. 5,033,818 discloses a diving system including a dive computer attached to an air tank and a wire which directs signals arriving from the dive computer onto the display in the diving mask, and from here onwards through optical means to the lens of the mask to be viewed by the diver.
International application WO 88/106549 discloses a diving system comprising a dive computer and means for providing a signal wirelessly on the display. The display is either in the mask or apart from it.
Professionals in diving also know a wrist-mounted relatively compact dive computer provided with a display, the design of which resembles a conventional wrist watch and like the conventional wrist watch includes straps and a time display. Such an apparatus is marketed by Suunto Oyj and is referred to as SPYDER and is known as a dive computer watch. The dive computer watch is also associated with abbreviation ACW, which is short for Advanced Computer Watch. The dive computer watch informs about various dive data, such as depth, time, stages of dive and ascent rate. The watch functions of the apparatus are versatile. The dive computer watch is mostly kept on the wrist for telling time, in which case the apparatus has a certain status symbol. The value of the apparatus is in fact so great that it is purchased by other people as well, not only by active divers. When the apparatus is used during a dive it is still mounted on the wrist in a conventional manner.
All the above apparatuses are relatively expensive. The last mentioned one, or the dive computer watch, however, stands out from the other dive computer apparatuses, as it functions as a very reliable watch as well, and can be used everyday. Thus, it is a versatile device with value beyond diving.